First set up your two equations:
x + y = 90
x = 2y - 30
Then substitute what x equals in the second equation into the first equation:
(2y -30) + y = 90
Now solve for y:
3y -30 = 90
3y = 120
y = 40
Then use y = 40 and substitute the value for y into one of your original equations and solve for x. I'll choose the first one, but either one will work.
x+ 40 = 90
x = 50
So your solution is x = 50 and y = 40
Answer:
Step-by-step explanation:
-3x^4 -9x^3+ 15x^2
-3x^2 ( x^2 + 3x -5)
if you use quadratic formula (see image)
~~~~~~~~~~~~~~~~~~~~~~
10x^3 -35x^2 +6x -21
5x2(2x-7) +3(2x-7)
(5
+ 3) (2x-7)
Answer:
72 books will fit on the shelf
Okay so first, area is length times width, so 1/4x*x would be first = 1/4(x^2)=64. Then area or x = 16 or -16
perimeter would be width times two plus length times two. I recommend using math papa to calculate these numbers.